ENB 110 Bridge Project Wiki
Welcome to the ENB 110 Bridge Project Wiki ENB 110 Group Project Design Criteria Design and construct a 1:100 scale model according to the design criteria: *Model must be a two span truss design *Model must be statically determinate and be capable of being analysed using the tree equations of equilibrium *Model will be 920mm long, 200mm wide and no more than 40mm deep *Truss material must be no more than 5mm x 4mm in cross section or 5mm diameter, approximately 20mm^2 cross section *Model will have one span secured at the end on the test rig. The test rig at the point holding the end down is 150mm wide and will fit on top of the end of the model between the side trusses. The forces that transfer the loads on the truss to the rig at this point will need to be taken on the end cross member. The centre of the model will need to be supported on the rig by some sort of pier as the height from the top of the model to the centre support is 60mm. The second span then cantilevers out from the centre pier to a free end. *Height limit from level of bridge deck to bottom of pier is 60mm *Other load bearing parts of the structure can be made from any suitable material *Model must be simply supported at the centre pier, but each truss needs to be connected to each other *No decking on the bridge, so that horizontal bracing of the bridge is taken by the structural bracing of the model *Test rig will supply loads through a 400x150mm plate to be placed on the cantilevered section with one end of the plate on the end of the cantilevered section. There needs to be space in the centre of the bridge, 200mm from the end, for the load to be applied to the underneath of the loading plate. *The model must be able to support a reasonabe side load applied at the end of the cantilever deck *Test rig will be made available before the testing day to ensure that the bridge can fit the test rig. *No construction or testig is to be carried out on the QUT premises Group Meeting #1 Tuesday 3rd April, 2012 Attendee's Alec, Nick, Brad, Jason, Samual Absentee's/Apologies Mohammed Topics for discussion generally revolved around first clarifying individual perceptions of the project outcomes at a general level. Followed by how our team can progress to the next stage. We brainstormed some research avenues for individuals to chase. If you can think of more of these guys, then please feel free to email Research Avenues: Person researching *Different Material Yield points( to ease the choice when it comes to having our bridge plasticly fail at about 25-30kg on the test rig) -- Alec *Costings for assorted materials, fixing, etc(Uni students are notoriously poor) -- Sam *Design types, and any pre-made formula's for specific designs that might exist -- Brad *Report Layouts, information required, formats, etc -- Jason *The math on calculating failure for assorted extrusions of metals, IE metal strips or angeline --Nick Group Meeting #2 =ladies and gentlemen, i reread the proforma for the project, there is a limitation on materials to be used, in that any long members may not have a cross-sectional dimension greater than 5mm*4mm or a cross sectional surface area of 20mm^2 {C}so ullrich is useless as nothing they sell is in this range.......... {C}again i pray for us to use balsa, i suggest buying up 2 of each square section long members size from 4mm square and down to test tension and compression failure with a pulling and a crushing test to be devised at a later date {C} i've worked out so far that one of our cords will be in compression and one in tension, with regards to cross sectional area of long members, members in compression need to be thicker than members in tension, due to buckling possibilities and the properties of most suitable materials, ie, metals are stronger in tension than compression so cross sectional area to support the same weight must be bigger when in compression than for tension, ie, make a stand to hold 1 tonne and make a rope to hang 1t from, the difference in required materials is huge hope i'm not rambling, will continue with this, intend to work up a full FBD for this sucker, hopefully getting a 3d model done at some point aswell, have more of an understanding about the floor members, would love to do more of this stuff perhaps before the next meeting, depending on peoples availability {C}meeting minutes, we acknowledge that everyone showed up, sam gave apology and notice of arriving late, mohammed showed up late(more participation please) {C}Team reflection? -overall, we acheived our distributed goals from the first meeting, whilst hemorraged a member who dropped out of this semester, some expectations were vague and overall future goals left vague aswell. -Outside of the meeting, i think we're not clear enough on the constraints, and or the templates that exist perhaps? -I also admit personally to a lack of organizational skills in coordinating the meeting over the break, which has led to some stunting of progress = Group Meeting #3 I scanned the pages i cobbled together, the circled letter next to tasks means were vaguely allocating that arena to you for the moment, talk about it more on thursday, and i'll try to writeup more later Group Meeting #4 We met tuesday(qut), wensday(qut) and friday(sams house) made the test rig, albeit not ideal to our needs, and we performed some initial testing with compression of balsa wood lengths. Testing was performed at sams house, and throughout the proccess all members were in attendance at some point and involved in the testing Alec managed a table of contents with some outlines for content will upload receipts and expenditure details when i remember to scan mine and alec's receipts and get receipt info for Mohammeds parts Objective to meet wk9 wensday, then attempt to build some truss sections on the following sunday Group meeting #5 Met generally through the day on wensday wk9, So far everyone has come along at some point, Mohammed? Alec and nick are working on statically determinate trusses, Sam has made up a cad model of the truss to the level of guide lines for 2-force members, brad is working on crfeating some truss sections to test with on sunday organized another meeting for sunday at sams house for further testing, a serious priority for the moment is to find out the loadings on individual members based on statically determinate truss modelling. attached is a pic of the cad drawing i knocked up and screen shotted because my cad knowledge is functional and adhoc, not awesome Latest activity Category:Browse Category:Group Meetings